The EHEIM Jager Thermocontrol (also sold as the EHEIM Jager TruTemp) is the classic German-made aquarium heater trusted by fishkeepers for decades. Set your temperature once, and its precise thermostat holds it to within ±0.5 °C — for healthy, stress-free fish in freshwater, planted and marine aquariums.
Why aquarists choose the EHEIM Jager
- Made in Germany — EHEIM build quality with a long track record.
- Precise temperature control — adjustable from 18 °C to 34 °C, held to ±0.5 °C.
- Re-calibratable (±2 °C) — if your thermometer reads differently, you can fine-tune the heater to match it.
- Dry-run protection (Thermo Safety Control) — switches off automatically if the heater is ever run out of water.
- Special laboratory glass jacket — bigger heating surface and even heat spread, with a built-in heat shield.
- Control lamp — shows at a glance when the heater is working.
- Fully submersible and watertight; fresh and saltwater safe.
- ~170 cm cable and double suction-cup holder included.
Which wattage do I need?
| Model | Recommended tank | Maximum tank | Length | EHEIM art. no. |
|---|---|---|---|---|
| 100 W | approx. 100 L | up to 150 L | 319 mm | 3614010 |
| 200 W | approx. 300 L | up to 400 L | 406 mm | 3617010 |
| 300 W | approx. 600 L | up to 1000 L | 506 mm | 3619010 |
Tip: if your room gets cold in winter or your tank sits near the upper limit, choose the next size up — the heater will work less hard and last longer.
Specifications
| Temperature range | 18 – 34 °C |
| Control accuracy | ± 0.5 °C |
| Re-calibration | ± 2 °C |
| Diameter | 36 mm (all models) |
| Cable length | approx. 170 cm |
| Housing | Special laboratory glass |
| Safety | Dry-run protection (Thermo Safety Control) |
| Water type | Freshwater & saltwater |
| Made in | Germany |
In the box
- EHEIM Jager Thermocontrol heater
- Double suction-cup holder
- Instructions
How to use
- Fix the heater with the suction cups in an area with good water flow, vertically or at an angle.
- Keep it submerged to at least the minimum water-level mark.
- Wait about 15 minutes after placing it in the water before plugging in, so the glass adjusts to the water temperature.
- Set your target temperature and check it with a thermometer after a day.
Safety: always unplug the heater before water changes or before lifting it out of the tank.
Frequently asked questions
Is "EHEIM Jager" the same as "EHEIM Thermocontrol"?
Yes — Thermocontrol is the current name of the EHEIM Jager heater line (also sold as Jager TruTemp in some markets).
Can I use it in a marine / reef tank?
Yes, it is suitable for both freshwater and saltwater.
Need electronic control for a very large tank?
See the EHEIM Thermocontrol e electronic heater (300W / 400W).
Genuine EHEIM product, shipped from Astra Aquatics, Chennai. Not sure which size fits your tank? Contact us and we'll help you choose.